Mine also starts pushback at exactly 13mph in extreme. This is consistent with what fm stated for extreme as opposed to classic's 10mph pushback. Not sure how hat jives with the whole 15mph top speed specs when I have never been able to get that fast.

I'd say it could have something to do with weight but given how close to 13mph pushback starts for me I'd assume weight is not in play for my board.

I'm fine with 13mph if that limitation is needed for safety given current specs but if not I would not mind going a little faster.

You have to leave your phone screen on (unlocked), which is of course tricky when putting the phone back in your pocket. Even then, after a few minutes, the watch will switch back to the clock unless you're raising your wrist and checking it every 30 seconds.

How do you guys keep your Apple Watch app connected? Once I put my phone back in my pocket, the connection is lost after a minute of so...

So, after the recent update the phone screen could be turned off and the watch remained connected. Even waited a couple of minutes. The downside of it defaulting to the clock remains. Hopefully we could add it to the "Glances" in the future.